[PATCH v2] of: add functions to count number of elements in a property
From: mark.rutland@arm.com (Mark Rutland)
Date: 2014-01-17 16:54:11
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linux-devicetree, lkml
On Fri, Jan 17, 2014 at 03:44:14PM +0000, Heiko St?bner wrote:
quoted hunk ↗ jump to hunk
The need to know the number of array elements in a property is a common pattern. To prevent duplication of open-coded implementations add a helper static function that also centralises strict sanity checking and DTB format details, as well as a set of wrapper functions for u8, u16, u32 and u64. Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Heiko Stuebner <heiko@sntech.de> --- changes since v1: address comments from Rob Herring and Mark Rutland: - provide a helper and a set of wrappers for u8-u64 - get rid of extra len variable, prop->length is enough - include node name in error message drivers/of/base.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/of.h | 32 +++++++++++++++++ 2 files changed, 130 insertions(+)diff --git a/drivers/of/base.c b/drivers/of/base.c index f807d0e..b6e6d4a 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c@@ -862,6 +862,104 @@ struct device_node *of_find_node_by_phandle(phandle handle) EXPORT_SYMBOL(of_find_node_by_phandle); /** + * of_count_property_elems_of_size - Count the number of elements in a property + * + * @np: device node from which the property value is to be read. + * @propname: name of the property to be searched. + * @elem_size: size of the individual element + */ +static int of_count_property_elems_of_size(const struct device_node *np, + const char *propname, int elem_size)
As a minor nit, it would be nicer to have 'count' and 'property' switch places in the name (i.e. call this of_property_count_elems_of_size). That way it's concistent with the naming of the wrappers.
+{
+ struct property *prop = of_find_property(np, propname, NULL);
+
+ if (!prop)
+ return -EINVAL;
+ if (!prop->value)
+ return -ENODATA;
+
+ if (prop->length % elem_size != 0) {
+ pr_err("size of %s in node %s is not a multiple of %d\n",
+ propname, np->name, elem_size);It would be nice to use np->full_name so you get the absolute path of the node -- it makes finding them easier later. Otherwise, the patch looks good to me, thanks for implementing it! With those changes: Reviewed-by: Mark Rutland <mark.rutland@arm.com> Cheers, Mark.